The present invention relates to a motor driven sander specifically designed to smooth curved surfaces.
Conventional power sanders typically include a motor driven sanding belt wrapped about a plurality of rollers to form a continuous loop. The portion of the loop that contacts the surface to be sanded is usually flat and is generally not suitable for smoothing curved surfaces such as those found on various furniture items, automobile parts and similar products. W Accordingly, there is currently a need for a device having a motor driven sanding belt which may be selectively bent to sand a curved surface.
Various sanding devices some of which purport to grind or smooth curved surfaces have been heretofore designed. For example, U.S. Pat. No. 5,545,077 issued to Boeck et al relates to a motor driven belt grinder with a plate tensioning means. An insert plate may be inserted into a slot to vary the distance between the motor housing and an attached case to selectively vary the tension of the belt.
U.S. Pat. No. 5,319,887 issued to Walz et al relates to a hand sander including a housing with a drive roller and a deflecting roller both rotatably supported therein; an endless sanding belt is guided along the deflecting roller and an attached guide plate.
U.S. Pat. No. 4,587,770 issued to Lindberg relates to a belt sander attachable to a portable drill for sanding curved or flat surfaces. The device includes a frame having a drive roller and an idle roller with a movable carriage carrying a second idle roller. A combined guard plate and pressure guide enables guidance and application of sanding pressure by the user.
U.S. Pat. No. 4,334,390 issued to Sumerau relates to a motor driven belt sander having a low profile and a center of gravity close to the sanding plane. A belt is placed about three triangularly disposed drums with the motor disposed within the belt path. The motor and a support mechanism is mounted to a one piece frame which hangs from the housing.
U.S. Pat. No. 3,611,646 issued to Cameron et al relates to an apparatus for supporting the pulley of a belt grinder in which the attachment angle may be varied.
U.S. Pat. No. 3,417,511 issued to Dudek relates to a belt sander having means for directing cooling air from the motor to the belt as well as a special bearing arrangement that minimizes resistance due to binding between the parts of a tensioning means.
Although at least one sander exists in the prior art that is designed to smooth curved surfaces, none relate to a simple, versatile device employing a sanding belt which may be selectively conformed to a variety of surfaces. The present invention provides a motor driven sanding belt driven along a continuous path, a section of which defines a sanding portion. The curvature of the sanding portion may be selectively varied to conform to various curvilinear surfaces.
The present invention relates to a unique motor driven sander for smoothing curvilinear surfaces such as those found on furniture items and automobile parts. A first embodiment is preferably mounted to a table top or a similar horizontal support surface. A pair of spring biased circular plates are pivotally secured to the lower side of the horizontal support surface each immediately below an inner and outer arcuate slot on the support surface. A pair of idler rollers and a drive roller are disposed on the top side of the support surface in a substantially triangular configuration. Each idler roller is immediately above an inner slot and is secured to the pivoting plate therebelow allowing the roller to reciprocate within the slot. A continuous sanding belt is wrapped around the idler and drive rollers which drive the belt along a substantially triangular path. The section of the path between the two idler rollers forms a sanding portion. Within the boundary of the belt immediately adjacent the sanding portion is a flexible, vertical plate having an anchor post at each of two opposing sides thereof. Each anchor post is disposed within an outer arcuate slot and is likewise secured to one of the pivoting circular plates therebelow. Proximal the inwardly facing side of the flexible plate is a movable engagement member having an arcuate outer edge immediately adjacent the plate. When the arcuate edge is thrust against an intermediate portion of the flexible plate, the plate bends and simultaneously engages the belt causing the sanding portion to assume a curved orientation. The curvature of the sanding portion may be selectively varied by moving the plate a desired distance. A fixed block is immediately adjacent the engagement member having a bolt therethrough an end of which impinges the inner edge of the engagement member to move it back and forth. The drive roller is rotated with a motor means disposed on the lower side of the horizontal support surface.
A second embodiment relates to a hand held sander including a handle member having a flat blade extending therefrom. On a first side of the blade are a plurality of idler rollers and a drive roller with a continuous sanding belt wrapped thereabout. A semicircular engagement member similar to that of the first embodiment is attached to the blade immediately adjacent the belt, preferably the lower portion thereof. On an opposing side of the blade is an adjustment knob for displacing a plate resting on the upper surface of the engagement member to move the lower semi-circular edge up and down to vary the curvature of the sanding portion. It is therefore an object of the present invention to provide a sander which can effectively smooth curvilinear surfaces.
It is yet another object of the present invention to provide a sander having an arcuate sanding portion, the curvature of which may be selectively varied.
It is yet another object of the present invention to provide a sander which may effectively smooth various curvilinear surfaces using a hand held, easily transportable device. Other objects, features and advantages of the present invention will become readily apparent from the following detailed description of the preferred embodiment when considered with the attached drawings and the appended claims.